R help - Mar 2012 - Delete rows from data.frame matching a certain criteria

Hello,


consider the following data.frame:

test <- data.frame(n = c(1,2,3,4,5), v = c(6,5,7,5,3), pattern
c(1,1,NA,1,NA))
> test
  n v pattern
1  1     6       1
2  2     5       1
3  3     7      NA
4  4     5       1
5  5     3      NA


I tried to use apply and the adply function to set v to NA where pattern = 1
and v to v where pattern = 1


So basically the result should look like this:
> test
  n v pattern
1  1     NA       1
2  2     NA      1
3  3     7      NA
4  4     NA       1
5  5     3      NA

So far, I solved it by creating subsets and using merge but it turns out to
be super slow. Is there a way to do that
with the apply function?

Any help/hint is appreciated

Thanks


--
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Hi,

On Thu, Mar 1, 2012 at 11:11 AM, mails <mails00000 at gmail.com>
wrote:
> Hello,
>
>
> consider the following data.frame:
>
> test <- data.frame(n = c(1,2,3,4,5), v = c(6,5,7,5,3), pattern >
c(1,1,NA,1,NA))
>
>> test
> ?n v pattern
> 1 ?1 ? ? 6 ? ? ? 1
> 2 ?2 ? ? 5 ? ? ? 1
> 3 ?3 ? ? 7 ? ? ?NA
> 4 ?4 ? ? 5 ? ? ? 1
> 5 ?5 ? ? 3 ? ? ?NA
>
Thanks for the reproducible example.
> I tried to use apply and the adply function to set v to NA where pattern =
1
> and v to v where pattern = 1
Presumably that should be set v to NA where pattern == 1 and v to v where
pattern != 1
>
> So basically the result should look like this:
>> test
> ?n v pattern
> 1 ?1 ? ? NA ? ? ? 1
> 2 ?2 ? ? NA ? ? ?1
> 3 ?3 ? ? 7 ? ? ?NA
> 4 ?4 ? ? NA ? ? ? 1
> 5 ?5 ? ? 3 ? ? ?NA
> So far, I solved it by creating subsets and using merge but it turns out to
> be super slow. Is there a way to do that
> with the apply function?
Far too much work. What about:
> test$v <- ifelse(test$pattern == 1, NA, v)
> test
  n  v pattern
1 1 NA       1
2 2 NA       1
3 3 NA      NA
4 4 NA       1
5 5 NA      NA


-- 
Sarah Goslee
http://www.functionaldiversity.org

Your criteria did not make sense since in both cases pattern == 1, so
I chose to set to NA if pattern == 1
> test <- data.frame(n = c(1,2,3,4,5), v = c(6,5,7,5,3), pattern +
c(1,1,NA,1,NA))
> test
  n v pattern
1 1 6       1
2 2 5       1
3 3 7      NA
4 4 5       1
5 5 3      NA
> # set v to NA when pattern = 1
> test$v[!is.na(test$pattern) & (test$pattern == 1)] <- NA
> test
  n  v pattern
1 1 NA       1
2 2 NA       1
3 3  7      NA
4 4 NA       1
5 5  3      NA
>
>

On Thu, Mar 1, 2012 at 11:11 AM, mails <mails00000 at gmail.com>
wrote:
>
> Hello,
>
>
> consider the following data.frame:
>
> test <- data.frame(n = c(1,2,3,4,5), v = c(6,5,7,5,3), pattern >
c(1,1,NA,1,NA))
>
> > test
> ?n v pattern
> 1 ?1 ? ? 6 ? ? ? 1
> 2 ?2 ? ? 5 ? ? ? 1
> 3 ?3 ? ? 7 ? ? ?NA
> 4 ?4 ? ? 5 ? ? ? 1
> 5 ?5 ? ? 3 ? ? ?NA
>
>
> I tried to use apply and the adply function to set v to NA where pattern
> 1
> and v to v where pattern = 1
>
>
> So basically the result should look like this:
> > test
> ?n v pattern
> 1 ?1 ? ? NA ? ? ? 1
> 2 ?2 ? ? NA ? ? ?1
> 3 ?3 ? ? 7 ? ? ?NA
> 4 ?4 ? ? NA ? ? ? 1
> 5 ?5 ? ? 3 ? ? ?NA
>
> So far, I solved it by creating subsets and using merge but it turns out
> to
> be super slow. Is there a way to do that
> with the apply function?
>
> Any help/hint is appreciated
>
> Thanks
>
>
> --
> View this message in context:
>
http://r.789695.n4.nabble.com/Delete-rows-from-data-frame-matching-a-certain-criteria-tp4435414p4435414.html
> Sent from the R help mailing list archive at Nabble.com.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.



--
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of mails
> Sent: Thursday, March 01, 2012 8:11 AM
> To: r-help at r-project.org
> Subject: [R] Delete rows from data.frame matching a certain criteria
> 
> Hello,
> 
> 
> consider the following data.frame:
> 
> test <- data.frame(n = c(1,2,3,4,5), v = c(6,5,7,5,3), pattern >
c(1,1,NA,1,NA))
> 
> > test
>   n v pattern
> 1  1     6       1
> 2  2     5       1
> 3  3     7      NA
> 4  4     5       1
> 5  5     3      NA
> 
> 
> I tried to use apply and the adply function to set v to NA where
> pattern = 1
> and v to v where pattern = 1
> 
> 
> So basically the result should look like this:
> > test
>   n v pattern
> 1  1     NA       1
> 2  2     NA      1
> 3  3     7      NA
> 4  4     NA       1
> 5  5     3      NA
> 
> So far, I solved it by creating subsets and using merge but it turns
> out to
> be super slow. Is there a way to do that
> with the apply function?
> 
> Any help/hint is appreciated
> 
> Thanks
> 
> 
There is no need for apply here, this is a simple indexing problem.  Something
like this should work

test$v <- ifelse(is.na(test$pattern), test$v, NA)


Hope this is helpful,

Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204